Oral vinorelbine (NVBO) in combination with trastuzumab (HER) in metastatic breast cancer (MBC): Data on efficacy and safety when administered in first- or second-line treatment.

Abstract

e11508 Background: Vinorelbine plus HER is an active and well-tolerated regimen in HER2-overexpressing MBC. When HER is administered every 3 weeks, the use of oral vinorelbine can increase the patient's convenience avoiding local toxicity. We report the retrospective results of our clinical experience on the combined regimen of HER and NVBO as first- or second-line treatment in HER2+ MBC. Methods: Between April 2005 and March 2009, 18 patients (p) with histologically confirmed, measurable MBC were treated in 8 Spanish institutions. Tumors scored as +3 positive for HER2 by inmunohistochemistry or FISH+. P could have received a prior treatment line with HER plus chemotherapy (CT). Treatment consisted of HER 8 mg/kg as a loading dose, then 6 mg/kg i.v. every 3 weeks, plus NVBO 80 mg/m2 days 1 and 8, with a prior test of myelosensitivity at 60 mg/m2 for the first cycle (cy), every 3 weeks. Treatment was continued until progression or unacceptable toxicity. Results: Patient's characteristics were: PS 0-1, 94%; visceral involvement in 100%; >2 metastatic sites in 50%. Prior (neo)adjuvant CT in 11 p (61%); type of CT: anthracycline 63%, anthracycline+taxane 27%. Prior hormonetherapy, 9 p (50%). Treatment was administered as first-line CT in 8 p (44%); second-line CT in 10 p (56%). Median number of cy 6 (range 3-12). We analyzed 121 cy. NVBO dose reduction was performed in 2.9% cy on D1 and 1.6% cy on D8. Hematological toxicities (%cy): grade (g) 3 anemia, 0.8%; no g3-4 neutropenia was reported. Nonhematological toxicities (%cy): g3 asthenia, 0.8%; g3 diarrhea, 3.3%; g3 nausea/vomiting 1.7%. All patients were evaluable for response. 5 CR (28%), 6 PR (33%), and 5 SD (28%) were reported. Objective response (OR) rate 61%. Median follow-up was 4.3 months (range 2.3-17.03), At the time of analysis, 3 p presented PD and 1 p had died. Conclusions: The findings of this retrospective analysis when compared to the reported data in the literature in this population suggest that the combination of three-weekly HER plus oral vinorelbine (80 mg/m2 D1 and 8) has a similar efficacy when compared to i.v. vinorelbine while avoiding venous toxicity and adding comfort to the day 8 administration. No significant financial relationships to disclose.